[Docs] Correct stale public documentation

[roomote-roomote]

Created by Roomote. Follow up by mentioning @roomote-roomote or in the web UI.

What changed

• corrected setup requirements for self-hosting, local development, Linear, Snowflake, and Azure DevOps
• aligned task-entry, attachment, telemetry, model credential, environment schema, and compute-provider guidance with current runtime behavior
• repaired stale source-control and Dev Container links and corrected the documented favicon asset

Why this change was made

The public docs had accumulated several claims that no longer matched current configuration schemas, provider behavior, and integration setup flows.

Impact

Operators and users now get accurate prerequisites, permissions, security caveats, supported values, and task-entry instructions across the affected documentation pages.

[roomote-community]

No code issues found. See task

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